Expert Advice:

Go to School: Van Cleef & Arpels runs a weeklong jewelry seminar in Paris; the next is Sept. 17-20. The Sotheby's Institute in London offers day courses; one on fine jewels is coming up in late November. Ms. Druckenmiller has sent staffers to the annual Antique Jewelry & Art Conference (jewelrycamp.org). Verdura owner and jewelry expert Ward Landrigan recommends the permanent jewelry collection at the Victoria & Albert Museum in London as "the best learning experience I know."

Do Your Homework: Before you buy, check auction results for similar pieces online. Mr. Landrigan also uses ArtFact.net to track sales. Ms. Price advises asking the seller as many questions as possible. If they balk, she said, "walk away."

Proceed With Caution: "I have never been a proponent of jewelry as an investment," said Mr. Landrigan. "But you should protect what you spend. Buy a brand name. Buy from someone you know. Establish a relationship."

ENLARGE

The most important point about shopping for vintage jewels: Know before you buy.
Juliana Sohn for The Wall Street Journal

ENLARGE

Vintage jewelries on display at F.D.
Juliana Sohn for The Wall Street Journal

IN 2010, WHEN Fiona Druckenmiller opened F.D., her New York gallery of rare vintage jewelry, furniture and decorative objects, she placed a large table embedded with a touch-screen near the entryway. The device could display images of the shop's entire inventory and offered customers access to the Internet (for checking auction results) and to various reference materials, including the "Dictionnaire des Poinçons," a trusted guide to jewelry makers' official marks.

"I hoped clients would use it to reference comparable pricing and to educate themselves about the hallmarks of various houses and designers," said Ms. Druckenmiller. The table, however, went unused for the most part—customers preferred to speak to a staffer instead of tapping on a screen—and was eventually donated to a charity. Her staff of seven, now armed with iPads, is always on hand to answer shoppers' questions and reinforce the most important point about shopping for vintage jewels: Know before you buy.

Ms. Druckenmiller began her own education in 1983, when she bought her first piece of antique jewelry, a delicate Edwardian emerald-and-diamond ring, from New York boutique Fred Leighton, "back when the shop was still selling Mexican wedding dresses," she said. Soon she started following jewelry auctions and collecting more seriously. "The jewelry world was a lot more opaque back then," she said. "Before the Internet and 1stDibs, there wasn't as much information and access."

Her personal collection has a few hundred pieces, from Van Cleef & Arpels, Cartier, Schlumberger for Tiffany & Co., and top-tier contemporary jewelers like JAR, Viren Bhaghat and Hemmerle. "Part of it is knowing what you'd actually wear," she said. "Unless it is just an investment that you're planning on selling, you should be wearing it and enjoying it."

While jewelry can be a fine investment, buying it solely as an asset is risky. Like any commodity, it's vulnerable to unexpected forces. Ms. Druckenmiller brought up the example of South Sea pearls, which were heavily coveted in the '90s. "Then they farmed so many, the supply-and-demand equation completely changed," she said. Pearls that had sold for hundreds of thousands of dollars were suddenly worth $10,000 to $20,000. Then again, prices for enameled Bulgari Serpenti watches have nearly doubled in the past year, and demand is still strong. "The trick is to find an asset that you also think is beautiful," she said. "And to wait to buy until you have both ingredients."

Ms. Druckenmiller said she opened F.D. primarily to help clients get their hands on pieces that they wouldn't be able to find elsewhere. Interior designer Muriel Brandolini, a friend and client, calls F.D. "the ultimate cabinet of curiosities." Now that the touch-screen table is gone, visitors who enter the pocket-size space are greeted by a gilded "Rhinocrétaire" desk by François-Xavier Lalanne displaying small decorative objects. Showcased prominently in a nearby vitrine are two David Webb pieces—a coral ring and a gold "Double Dragon" bangle—bought from the frenzied 2011 Christie's auction of Elizabeth Taylor's collection.

On a recent afternoon, Ms. Druckenmiller, pointed out a pair of Boivin ear clips in gold and diamonds that cover the entire ear. "I could see someone crazy wearing those to the Met Ball," she said. The less crazy might choose a '70s Aldo Cipullo nail bracelet, or one of a few Bulgari gold coil Serpenti watches—both of the moment. What's never out of vogue—or demand—are pieces from the Art Deco period, of which she has a healthy stock. "There's never going to be any more supply," she explained. "No one works in platinum, and the quality of those stones is just not available anymore."

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